I think it's not clear whether one who entered with AP can stay on H1 "status" although H1 as an employment authorization is valid.
My understanding is that extending H1 under such circumstance reinstates H1 status, but till that happens, one remains parolee status. Not sure what happens to derivative H4 in such a case.
It might be interpretted differently by lawyers, but here is one interpretation.
http://www.immigration-law.com/
05/05/2005: Approaching Summer Travel Season and H-1B Traveling With Advance Parole
Summer is on our door step and schools will take a long break allowing students and employees of the schools to take a vacation and traveling abroad. There are a substantial number of EB-485 filers who maintain a H-1B status and at the same time possess an Advance Parole. Some of these EB-485 filers may want to travel on Advance Parole rather than on H-1B because of the complication and delay in obtaining the H-1B visa stamp at the visa posts.
People are confused as to whether they can return to the U.S. using Advance Parole and continue the H-1B employment without EAD. The answer to this question is confusing because the legacy INS flip-flopped itself in the past. Initially, it was policy that such H-1B alien who returns to the U.S. without EAD could not work as he/she was no longer H-1B nonimmigrant and did not have employment authorization. However, this memorandum was short-lived, being later amended and rescinded.
The current rule is that the H-1B aliens who return to the U.S. using Advance Parole will be able to resume the employment authorization which is inherent in the H-1B status inasmuch as the following conditions are met: (1) The employment is resumed with the same H-1B employer. (2) The H-1B approval must remain valid, even though one does not need a valid H-1B visa stamp. Once the H-1B validity expires, so does the employment authorization. Such an alien cannot continue employment unless he/she obtains either EAD or extension of H-1B status.
The H-1B alien is returning to the U.S. as a parolee when they use Advance Parole and their status remains a parolee and not a H-1B nonimmigrant, but current rule and policy allow such H-1B approved aliens two benefits pending finalization of its policy on this issue and release of a regulation.
The first benefit is employment authorization during the period of valid H-1B approval even though his/her status is no longer H-1B. The second benefit is eligibility for extension of their H-1B status and
resuming the H-1B status without leaving the country.
Once extension is approved, the alien returns to the H-1B status. The approval of such H-1B extension is considered by the USCIS as revocation of the parolee status and reinstatement of the H-1B status. These travellers should make it sure that they have both valid H-1B approval paper and valid Advance Parole when they return from the trip. Again, the EAD is not necessary inasmuch as he/she has a valid H-1B approval. However, against the potential change of employment or loss of H-1B jobs, it will be always prudent that one keeps an EAD current all the time. Enjoy your Summer!!